I’ve been looking forward to the movie adaptation of Annihilation for a long time, largely because I really enjoyed the book and also because of one specific reason: the cast of the book is, with one exception, entirely female. This is a big deal, since the story revolves around a bunch of highly-educated, idiosyncratic scientists going into what is essentially the Everglades if the Everglades were a haunted house. I was disappointed to see such a big name as Oscar Isaac cast in the movie, though I enjoy him in most things, because I knew that would mean that his role as the husband was intended to be expanded. I rationalized that this was probably a good thing. After all, his death in the book is the entire emotional impetus for the Biologist’s entry into the psychotropic-murder-swamp that is Area X. It made sense that he would have a bigger role.

That impetus, at least, did not change.

(SPOILERS, if you haven’t figured that out yet.)

The movie kept a lot of things to love about the book, including the general creep-fest that is Area X. It jettisoned a lot of other things. Some of this was good. All of the characters got names, for example. There was no magical hypnosis to control their minds, and Area X was a bit closer than I expected, but overall they made some good decisions with that. I was also gratified that, when the husband – called Kane in the movie – did show up, the awkward sex scene didn’t happen. I was not particularly into that sex scene, for obvious reasons to do with consent, though it worked in the book in ways it would never have been able to work in the movie.

That’s about the end of the good changes, I think.

As a whole, the narrative the movie went with was not terrible, but it was not exceptional either. While there was no way that the movie could have stayed entirely true to the book – different mediums being what they are – my dominant feeling coming out of this movie was a sense of disquiet. That disquiet had nothing to do with the giant monster-animals eating people’s throats out to steal their voices, though that was creepy. It had a lot more to do with the fact that Oscar Isaac had such a central role in this film, as I had suspected. In the book, the Biologist goes into Area X to find her husband, or at least find out what happened to him. It is clear from early on that the doppleganger that returns is not him, but a copy, and a malformed one. The Biologist is an ecologist, and she relishes the diversity and fecundity of the newly reclaimed landscape, free of human contamination. Her connection with Area X is almost as personal as her relationship with her husband by the end, who, by the way, she does not find in the first book. Instead, we are left to guess at their story. Did she drown? Did she meet him on the island? Are they living together, still, or dead together, their ghosts haunting this new world?

In contrast, the doppleganger of Kane survives. Lena, the biologist, sets out to eradicate the thing that has threatened her love with her hard-earned military skills. She finds video of her husband at several places, including video of his death. Because of the loss she has experienced, she treats Area X like a cancer, not a cleansing. She burns it. And when she comes home she gets a happy-ever-after with Kane’s echo, miraculously alive.

Kane’s fate remains central to Lena’s story, but not in the way that the husband’s fate is central to the story of the Biologist. There are relatively few points of dialogue in the movie that do not center around Kane or Kane’s all-male team. (I cannot think of an instance of dialogue that does not at some point mention Kane or Kane’s team once they have entered Area X, excepting perhaps the scene with the alligator.) There are also three named male characters in this adaptation, one of whom was invented from whole-cloth to cast Lena as an adulterer, a confusing decision at best. I believe this was supposed to be a way to rationalize Kane’s decision to enter Area X, but it felt like an excuse to show Natalie Portman naked. Keep in mind that this is an adaptation of a book told entirely from a female scientist’s perspective, one whose central themes include a profoundly ecological bent (entirely removed in this on-screen iteration), and where the only male character dies within the first two chapters and lives primarily as a ghost in the narrator’s head.

It is disappointing to watch a movie that might have, in a better world, taken a diverse female cast and given them a gripping, cerebral storyline that didn’t revolve around men – and which fails to do so. Annihilation was not a terrible movie, taken out of the context of the source text. I do not hate it. But there was so much potential for what it could have been. And despite numerous things done right, the movie fell short of that potential.